Add json cache to lovelace config (#117843)

homeassistant/components/lovelace/dashboard.py

@@ -7,14 +7,16 @@ import logging
 import os
 from pathlib import Path
 import time
+from typing import Any
 
 import voluptuous as vol
 
 from homeassistant.components.frontend import DATA_PANELS
 from homeassistant.const import CONF_FILENAME
-from homeassistant.core import callback
+from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import collection, storage
+from homeassistant.helpers.json import json_bytes, json_fragment
 from homeassistant.util.yaml import Secrets, load_yaml_dict
 
 from .const import (
@@ -42,11 +44,13 @@ _LOGGER = logging.getLogger(__name__)
 class LovelaceConfig(ABC):
     """Base class for Lovelace config."""
 
-    def __init__(self, hass, url_path, config):
+    def __init__(
+        self, hass: HomeAssistant, url_path: str | None, config: dict[str, Any] | None
+    ) -> None:
         """Initialize Lovelace config."""
         self.hass = hass
         if config:
-            self.config = {**config, CONF_URL_PATH: url_path}
+            self.config: dict[str, Any] | None = {**config, CONF_URL_PATH: url_path}
         else:
             self.config = None
 
@@ -65,7 +69,7 @@ class LovelaceConfig(ABC):
         """Return the config info."""
 
     @abstractmethod
-    async def async_load(self, force):
+    async def async_load(self, force: bool) -> dict[str, Any]:
         """Load config."""
 
     async def async_save(self, config):
@@ -77,7 +81,7 @@ class LovelaceConfig(ABC):
         raise HomeAssistantError("Not supported")
 
     @callback
-    def _config_updated(self):
+    def _config_updated(self) -> None:
         """Fire config updated event."""
         self.hass.bus.async_fire(EVENT_LOVELACE_UPDATED, {"url_path": self.url_path})
 
@@ -85,10 +89,10 @@ class LovelaceConfig(ABC):
 class LovelaceStorage(LovelaceConfig):
     """Class to handle Storage based Lovelace config."""
 
-    def __init__(self, hass, config):
+    def __init__(self, hass: HomeAssistant, config: dict[str, Any] | None) -> None:
         """Initialize Lovelace config based on storage helper."""
         if config is None:
-            url_path = None
+            url_path: str | None = None
             storage_key = CONFIG_STORAGE_KEY_DEFAULT
         else:
             url_path = config[CONF_URL_PATH]
@@ -96,8 +100,11 @@ class LovelaceStorage(LovelaceConfig):
 
         super().__init__(hass, url_path, config)
 
-        self._store = storage.Store(hass, CONFIG_STORAGE_VERSION, storage_key)
-        self._data = None
+        self._store = storage.Store[dict[str, Any]](
+            hass, CONFIG_STORAGE_VERSION, storage_key
+        )
+        self._data: dict[str, Any] | None = None
+        self._json_config: json_fragment | None = None
 
     @property
     def mode(self) -> str:
@@ -106,27 +113,30 @@ class LovelaceStorage(LovelaceConfig):
 
     async def async_get_info(self):
         """Return the Lovelace storage info."""
-        if self._data is None:
-            await self._load()
-
-        if self._data["config"] is None:
+        data = self._data or await self._load()
+        if data["config"] is None:
             return {"mode": "auto-gen"}
+        return _config_info(self.mode, data["config"])
 
-        return _config_info(self.mode, self._data["config"])
-
-    async def async_load(self, force):
+    async def async_load(self, force: bool) -> dict[str, Any]:
         """Load config."""
         if self.hass.config.recovery_mode:
             raise ConfigNotFound
 
-        if self._data is None:
-            await self._load()
-
-        if (config := self._data["config"]) is None:
+        data = self._data or await self._load()
+        if (config := data["config"]) is None:
             raise ConfigNotFound
 
         return config
 
+    async def async_json(self, force: bool) -> json_fragment:
+        """Return JSON representation of the config."""
+        if self.hass.config.recovery_mode:
+            raise ConfigNotFound
+        if self._data is None:
+            await self._load()
+        return self._json_config or self._async_build_json()
+
     async def async_save(self, config):
         """Save config."""
         if self.hass.config.recovery_mode:
@@ -135,6 +145,7 @@ class LovelaceStorage(LovelaceConfig):
         if self._data is None:
             await self._load()
         self._data["config"] = config
+        self._json_config = None
         self._config_updated()
         await self._store.async_save(self._data)
 
@@ -145,25 +156,37 @@ class LovelaceStorage(LovelaceConfig):
 
         await self._store.async_remove()
         self._data = None
+        self._json_config = None
         self._config_updated()
 
-    async def _load(self):
+    async def _load(self) -> dict[str, Any]:
         """Load the config."""
         data = await self._store.async_load()
         self._data = data if data else {"config": None}
+        return self._data
+
+    @callback
+    def _async_build_json(self) -> json_fragment:
+        """Build JSON representation of the config."""
+        if self._data is None or self._data["config"] is None:
+            raise ConfigNotFound
+        self._json_config = json_fragment(json_bytes(self._data["config"]))
+        return self._json_config
 
 
 class LovelaceYAML(LovelaceConfig):
     """Class to handle YAML-based Lovelace config."""
 
-    def __init__(self, hass, url_path, config):
+    def __init__(
+        self, hass: HomeAssistant, url_path: str | None, config: dict[str, Any] | None
+    ) -> None:
         """Initialize the YAML config."""
         super().__init__(hass, url_path, config)
 
         self.path = hass.config.path(
             config[CONF_FILENAME] if config else LOVELACE_CONFIG_FILE
         )
-        self._cache = None
+        self._cache: tuple[dict[str, Any], float, json_fragment] | None = None
 
     @property
     def mode(self) -> str:
@@ -182,23 +205,35 @@ class LovelaceYAML(LovelaceConfig):
 
         return _config_info(self.mode, config)
 
-    async def async_load(self, force):
+    async def async_load(self, force: bool) -> dict[str, Any]:
         """Load config."""
-        is_updated, config = await self.hass.async_add_executor_job(
+        config, json = await self._async_load_or_cached(force)
+        return config
+
+    async def async_json(self, force: bool) -> json_fragment:
+        """Return JSON representation of the config."""
+        config, json = await self._async_load_or_cached(force)
+        return json
+
+    async def _async_load_or_cached(
+        self, force: bool
+    ) -> tuple[dict[str, Any], json_fragment]:
+        """Load the config or return a cached version."""
+        is_updated, config, json = await self.hass.async_add_executor_job(
             self._load_config, force
         )
         if is_updated:
             self._config_updated()
-        return config
+        return config, json
 
-    def _load_config(self, force):
+    def _load_config(self, force: bool) -> tuple[bool, dict[str, Any], json_fragment]:
         """Load the actual config."""
         # Check for a cached version of the config
         if not force and self._cache is not None:
-            config, last_update = self._cache
+            config, last_update, json = self._cache
             modtime = os.path.getmtime(self.path)
             if config and last_update > modtime:
-                return False, config
+                return False, config, json
 
         is_updated = self._cache is not None
 
@@ -209,8 +244,9 @@ class LovelaceYAML(LovelaceConfig):
         except FileNotFoundError:
             raise ConfigNotFound from None
 
-        self._cache = (config, time.time())
-        return is_updated, config
+        json = json_fragment(json_bytes(config))
+        self._cache = (config, time.time(), json)
+        return is_updated, config, json
 
 
 def _config_info(mode, config):

homeassistant/components/lovelace/websocket.py

@@ -11,6 +11,7 @@ from homeassistant.components import websocket_api
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import config_validation as cv
+from homeassistant.helpers.json import json_fragment
 
 from .const import CONF_URL_PATH, DOMAIN, ConfigNotFound
 from .dashboard import LovelaceStorage
@@ -86,9 +87,9 @@ async def websocket_lovelace_config(
     connection: websocket_api.ActiveConnection,
     msg: dict[str, Any],
     config: LovelaceStorage,
-) -> None:
+) -> json_fragment:
     """Send Lovelace UI config over WebSocket configuration."""
-    return await config.async_load(msg["force"])
+    return await config.async_json(msg["force"])
 
 
 @websocket_api.require_admin
@@ -137,7 +138,7 @@ def websocket_lovelace_dashboards(
     connection: websocket_api.ActiveConnection,
     msg: dict[str, Any],
 ) -> None:
-    """Delete Lovelace UI configuration."""
+    """Send Lovelace dashboard configuration."""
     connection.send_result(
         msg["id"],
         [

tests/components/lovelace/test_dashboard.py

@@ -1,6 +1,7 @@
 """Test the Lovelace initialization."""
 
 from collections.abc import Generator
+import time
 from typing import Any
 from unittest.mock import MagicMock, patch
 
@@ -180,6 +181,44 @@ async def test_lovelace_from_yaml(
 
     assert len(events) == 1
 
+    # Make sure when the mtime changes, we reload the config
+    with (
+        patch(
+            "homeassistant.components.lovelace.dashboard.load_yaml_dict",
+            return_value={"hello": "yo3"},
+        ),
+        patch(
+            "homeassistant.components.lovelace.dashboard.os.path.getmtime",
+            return_value=time.time(),
+        ),
+    ):
+        await client.send_json({"id": 9, "type": "lovelace/config", "force": False})
+        response = await client.receive_json()
+
+    assert response["success"]
+    assert response["result"] == {"hello": "yo3"}
+
+    assert len(events) == 2
+
+    # If the mtime is lower, preserve the cache
+    with (
+        patch(
+            "homeassistant.components.lovelace.dashboard.load_yaml_dict",
+            return_value={"hello": "yo4"},
+        ),
+        patch(
+            "homeassistant.components.lovelace.dashboard.os.path.getmtime",
+            return_value=0,
+        ),
+    ):
+        await client.send_json({"id": 10, "type": "lovelace/config", "force": False})
+        response = await client.receive_json()
+
+    assert response["success"]
+    assert response["result"] == {"hello": "yo3"}
+
+    assert len(events) == 2
+
 
 @pytest.mark.parametrize("url_path", ["test-panel", "test-panel-no-sidebar"])
 async def test_dashboard_from_yaml(